CVE-2023-42116 - CVE House
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Status published High CVE-2023-42116

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability

Vulnerability Description

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

Exim
Vulnerable Versions:
exim 4.95

Timeline

Official Publish: May 3rd, 2024
Last Modified: November 4th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses (CWE)

CWE-121

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1068 Exploitation for Privilege Escalation
Privilege Escalation
T1055 Process Injection
Defense Evasion
T1105 Ingress Tool Transfer
Command and Control
T1485 Data Destruction
Impact